Distance-gage.



` J. M. WASHBURN.

DISTANCE GAGE.

APPLICATION FILED SEPT. 13 19 11 Patented July 30, 1912.

2 SHEETS-SHEET 1.

J. M. WASHBURN.

- DISTANCE GAGE.

PPPPPPPPPPPPPPPPPP n.13, 1911.

I Patented July 30, 1912.

2 SHEETS-SHEET 2.

DISTAN (1E-GAGE.

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Application led September To all whom t may concern Be it known that I, JAMES MURRAY vWASH- BURN, a citizen of the United .Sta-tes, residing at Chicago, county of Cook, and State of Illinois, have invented a new and useful Distance-Gage, of which the following is a specification.

It is the object of the present invention to provide an apparatus suitable for indica-ting directly and wit-hout any mathematical calculations the dist-ance from the apparat-us or from the eye of an observer to a distant object; to provide a distance gage which is compact and portable in structure 'and which is adapted to indicate directly in linear units distances ranging from about four to one hundred feet. y

To accomplish these and other objects the present invention embraces an arrangement which may be designated as a sight bar and which carries at one end a light deiiecting device, such as a prism, whereby a divergent ray of light from a distant object may be transmitted to the eye of the observer in such a way that it will converge with a ray of light passing directly from the distant object to the observers eye.

The sight bar is arranged at a definite angle to the direct line f sight toward the object and is calibrated to read directly in linear units the distance either from the sight bar to the object, or from the observerseye to the object. The prism may be adjustable along the sight bar and if desired may be replaced by compound mirrors or other arrangements'suitablefor fulfilling the functions'of a prism as herein set forth.

The specific embodiment herein described is intended particularly for the use. of contractors, carpenters and structural workers,

who are enabled ,by its use to gage quickly the dista-nce to various parts of a structure or building. I am aware', however, that the basic principles underlying my present invention are widely applicable and can be ,I used in photography and in other arts wherein relatively short distances are to. be

measured with high speed and reasonable accuracy.

In the accompanying drawings Figure 1 is a perspective view of a complete distance gage folded up for carrying in the pocket. Fig. 2 is a perspective view of the gage unfolded for use, the dotted lines indicating roughly the paths oflig'ht from a distant obiect not shown. Fig. B'isaplan of the Specification of Letters `Patent.

Patented July 30, 1912.

13,'1911. Serial No. 649,087. y

" gage showing the sight and the prism in secof the folding member of the gage.l Fig. 5 is a section through the sight bar immediately adjacent to the prism. Fig. 6 illustrates a modification wherein the prism instead of being slidably mounted on the sight bar is stationary and is of such length as to embrace the entire calibrated scale of the bar. Fig. 7 is a perspective view of this modification unfolded for use. Fig. S is a plan View showing the sight and the sta- .tionary prism in section.l Fig. 9 isa [sectional elevation through a pair of stationary ing device in place of the prisms shown in the preceding figures.

In the construction illustrated by Figs. l to 5 inclusive, the distance gage comprises a sight bar 1, carrying at one end a sight 2 and carrying at its other end a prism which is mounted tol slide along the sight preferably a thirty degree prism and has across its front face a Vertical line or crosshair 4 useful in sighting on a distant object. The prismis mounted in a metal box which is supported on a rod 5 carried in ears 6 and 7 which project upward from the flat upper' face of the sight bar. Immediately in front of the prism is a depending apron 8 marked off into a scale and cooperating with the cross-hair on the face of the prism to indicate directly in linear units, such as feet, the distance to the distant obj ect. This scale may be calibrated either to indicate the distance from sight 2 to the object or from t-he observers eye to the object, as desired. y The lower back corner of the prism-supporting asillustrated in-Fig. 1.

The sight 2 has a V shaped opening with a central sight line 10 and is hinged at 11 so that it may be folded down into small compass. For the proper use of the sight bar and its associated parte, it is necessary to locate the bar at a definite distance from the eye of the operator. IIn the specific embodiment illustrated inthe drawings of this application this function is fulfilled by a folding member made up of the sections 12 13 and 14 hinged ltogether and adapted to unfold, forming a rigid, straightl arm 'about eighteen twenty-four incheslong and carrying at its outer end the sight bar 1` of the bar as occasion may require. This prism is tion. Fig. 4 is a section through the joint mirrors adapted to serve as the light deflectbox is out away at 9 to permit folding down It is necessary that the sight bar should be arranged at a definite and predetermined angle to the folding arm, such for instance as a right angle, and to accomplish this result with certainty, the hinge between the sight bar and the folding arm may be constructed as illustrated in section, Fig. 4. A rivet 16 serves as a pivot for the joint and engages with the inner faces of metal sheathings 16 and 17, one of which envelops the edges of the folding arm and the other of which embraces the edges of the sight bar. One of the sheathings has indentat-ions 18 and 19 forming pockets intowhich corresponding projections 20 and 21 of the other sheathing may fit withla yielding engagement. By having four of these pockets as illustrated inFig. 3, the two connected members may be placed at right angles or in direct alinement and will maintain that relation until forcibly diverted therefrom by the operator. The -folding joints between the members 12, 13 and 14 are simila'rly equipped with sockets and projections so that they may be maintained in a straight line when once unfolded.

To use the distance gage, it is held withone end of the folding arm directly below an eye of the operator so that the direct line of sight from that eye -will pass through the sight box 2 to the distant object. Then the prism is moved inward and outward until the image of the distant objectappears to the operator as bi-sected by the cross-hair 4. The operator then reads from `the scale directly below the cross-hair and f this reading .indicates directly and without any mathematical calculations the distance in feet or other linear units from the eye of the operator to the distant object. In a certain sense the calibrated scale may be regarded as indicating the distance along the sight bar between the direct line of sight and the deflected line of sight, but the reading is not in distances along the bar, but

in distances at right angles therewith, that is, along the direct line of sight toward the distant object.

In the modification illustrated in Figs. 6 to 8 inclusive the prism 23 is rigidly mounted on the sight bar 24 and is covered and protected bya metal boxing 25, the corners of which are rounded oif so that the instrument can be easily carried in the operators pocket. The calibrated scale is carried on a depending apron which overlaps the other folding portions of the instrument when the structure is folded up for storage. t

The sight 26 comprises a bent metal archfrom which a sight point or line 27 extends downward. The folding arm vcomprises the hinged sections 28, 29 and 30 equipped with the spring joints as previously disclosed in connection with the other modification. In using the structure vshown in Fig. 7 the tant 'object distant object. The operator then looks' at` that object through the prism and then reads off vfromg the adjacent scale, taking the'value immediately below the image in the prism. This scale is so calibrated that the reading is one of linear units tothe distant object. As in the case of the modiiication first described, the prism may have an angular width of thirty degrees, though its length must be considerably greater to cover the same range of distances.

Although a prism has many'advantages as a means for deiiecting light to the observers eye as above described, other light deflecting means may be used, as for i1?- stance, 'the special arrangement of mirrors mirrors 3l and 32 held in a suitable box or frame work and set at such angles relative j to each other and to the axis of the sight bar, that light, coming from a distant object, will be deflected for transmission to the eye of the operator. Such a grouping of mirrors may be mounted in Xed position on a sight bar in place of prism 23 of Fig.- 8 or may be mounted to slide on the bar as in the case of prism 3 Fig. 2.

I aml aware that the basic ideas herein disclosed may be embodied in apparatus differing in many ways from those above described and that various modifications may be .constructed without departing from the spirit of my invention as defined 'by the appended claims.

Having described my invention, what I claim as new and desire to secure. by Letters Patent is:

1. A distance gage comprising a sight bar having at one end a sight which may be brought into alinement with a distant object, a light delecting device associated with said sight bar and in which an image of `to indicate dlrectly in linear'units the dis-` tance to said distant object, and means for positioning said bar in proper'relation to the eye of the observer.

2. In a distance gage, the combinationl of a sight bar, a sight carried by said bar, means for adjusting said sight bar into such position before an operators eye that a distant object may be Viewed in alinement with said sight, a light deflecting device through which said 4distant object may be seen by the operator and a calibrated scale laid olf-on said sight bar in position to indicate directly the distance to the dis- 13. In a distance gage the combination of 'a sight bar, a sight carried byx said bar,

means for supporting said bar at a vpredetermined distance from the eye of the operator in such position that a distant object may be viewed in alinement With said sight, means for controlling the angular position of said sight bar with regard to the direct line of sight to said object, a light deiiecting devicev through which said distant object may be viewed bythe operator, and a calibrated scale laid out along saidsight bar and coperating with said light deiecting device in the measurement of the distance to said distant object..

4. In a distance gage the combination of a sight bar, a sight on one end of said bar, a prism carried by the other end of said bar, a rigid arm for holding said bar at a predetermined distance from the eye of the 0perator and a scale laid out adjacent to said prism and'calibrated to indicate directly in linear units the distance from the leye of the operator to the distant object.

5. In a distance gage, the combination of a sight bar, an arm for supporting said bar, said arm comprising a plurality of folding sections, a spring joint between said bar and said arm to insure adjustment of said bar at right angles to said arm, a sight carried by said bar in direct alinement with said arm and in such position that when one end of the arm is at the operators eye said sight may be brought into alinement with a distant object, a prism carried by said sight bar and movable inward and outward thereon, and a scale adjacent to said prism and calibrated to indicate in linear units the distance to the distant object When that object appears in the prism. f

6. A distance gage comprising in combination-a sight bar, means -or gaging the proper distance at which said bar is to be held from the eye of the observer, means for insuring proper angular position of said bar with respect to the line of sight from the observers eye to a distant object, lightv delecting means associated with lsaid bar for bringing to the eye of the observer deflected light from said distant object, and a scale associated With said sight bar for gaging the divergence .of said deflected light, said scale being calibrated to indicate the distance. to the distant object.

In Witness whereof, I hereunto my name this 6th day of September A. D.V 1911.

JAMES MURRAY W/LrsHBURu. Witnesses: PAUL W. BAUMANN, v ABBA B. Marvin.

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